1. Technical Field
The present disclosure relates to an electrochemical hydrogen pump.
2. Description of the Related Art
In recent years, because of environmental issues, such as the global warming, and energy issues, such as depletion of oil resources, many attentions have been paid on a hydrogen gas as a clean alternative energy source instead of a fossil fuel. By combustion of a hydrogen gas, water is only emitted, and carbon dioxide, nitride oxides, and the like, each of which causes the global warming, are not emitted; hence, a hydrogen gas is expected as a clean energy source. As a device using a hydrogen gas as fuel, for example, a fuel cell may be mentioned, and for automobile power generation and in-house power generation, a fuel cell has been increasingly developed and spread. In addition, in a coming hydrogen society, technical development has been desired in which, besides hydrogen gas manufacturing, a hydrogen gas can be stored at a high density, and a small volume thereof can be transported or used at a low cost. Furthermore, in order to promote the spread of fuel cells, the infrastructure of fuel supply is required to be well organized. Hence, various proposals have been made in order to obtain a highly pure hydrogen gas by refining.
For example, Japanese Unexamined Patent Application Publication No. 2015-117139 has disclosed a hydrogen refining and pressure-boosting system in which by application of a voltage between an anode and a cathode with an electrolyte membrane provided therebetween, refining and pressure-boosting of a hydrogen gas are carried out. In addition, a laminate structure having an anode, an electrolyte membrane, and a cathode is called a membrane electrode assembly (hereinafter, abbreviated as “MEA”).
In this case, when a current flows between the anode and the cathode, protons move together with water molecules from the anode to the cathode through the electrolyte membrane. As a result, water (osmotic water) is generated from the water molecules on the cathode. Hence, according to Japanese Unexamined Patent Application Publication No. 2015-117139, in order to efficiently separate this water from a hydrogen gas, a water trap/drain unit is provided in a hydrogen gas flow path. The water trap/drain unit includes a pair of water traps provided with a drain valve. The hydrogen refining and pressure-boosting system disclosed in Japanese Unexamined Patent Application Publication No. 2015-117139 is formed in such a way that since the water traps are alternately switched so as to drain water out of the hydrogen gas flow path, water in the hydrogen flow path can be removed at an appropriate time even when the hydrogen refining and pressure-boosting system is continuously operated. Hence, highly pure hydrogen can be obtained by refining.